Spectrum sharing is thought of as one of the most viable ways of improving the amount of spectrum available to wireless networks and other radio devices for conducting wireless communications. An exemplary spectrum sharing technique involves use of television white spaces under regulations set forth by an appropriate regulatory agency. An exemplary regulatory agency that regulates the use of wireless spectrum is the U.S. Federal Communications Commission (FCC). Other countries may have similar regulatory entities.
In the U.S., for example, the FCC has eliminated analog television (TV) broadcasts in favor of digital TV broadcasts. This has freed spectrum channels for use by unlicensed radio systems to offer various services, such as mobile communications and Internet access. In this context, the freed spectrum is commonly referred to as TV white space (or TVWS) but other types of white spaces are possible. In the case of TV white space, the white space is comprised of unused spectrum that is interleaved with spectrum used by incumbent radio devices in the channel 2 to channel 51 range (corresponding to 54 MHz to 698 MHz). Exemplary incumbent radio devices for TV white space include television broadcasters and other priority users of television channels. Under FCC regulations, for example, radio devices that use TVWS must register with a central database server (also referred to as a spectrum management server) and receive a channel list (also referred to as a channel map) of available channels for which the radio device may use in a shared environment with other TV band devices (TVBDs). The channel list that is generated for a radio device is generated by the central database server based on the location of the radio device. In this manner, the operation of incumbent radio devices having protected areas in which the radio device is located may be taken into account when determining channel availability.
Also, regulators and industry groups have proposed the use of geo-location database technology to control or manage spectrum access for radios in other situations. For example, use of geo-location database technology has been proposed for the 5 GHz UNII bands and for the 3.550 GHz to 3.650 GHz bands in which the U.S. government and military are incumbent users.
Outside the U.S., use of geo-location database technology has been proposed for TVWS bands in a number of countries. In the European Union (EU), TVWS sharing is often referred to as authorized shared access (ASA) and/or licensed shared access (LSA). Exemplary regulations for ASA/LSA are outlined in European Telecommunications Standards Institute (ETSI) EN 301 598. Other standards bodies have also proposed mechanisms for supporting spectrum sharing, such as the Internet Engineering Task Force's (IETF) Protocol to Access White Space (PAWS).
A concern expressed by the operators of incumbent radio devices is how incumbent spectrum use will be protected from the potential effects of interference by TVBDs. The solution of choice is a geo-location database (e.g., the above-noted central database server) that is capable of managing the allocation of spectrum in accordance with policies defined in terms of geography, time, frequency and other parameters, such as transmit power and emissions characteristics.
Television broadcasters are just one type of protected spectrum user and this protection is by virtue of a spectrum license. Licenses are issued for a variety of other spectrum segments, typically defined by location, time, frequency and operating characteristics (e.g., antenna height, transmit power, etc.). Therefore, other incumbent devices that are entitled to interference-free use of spectrum include devices operating under regulatory license. Often, the license owners have paid substantial sums for the license. Other protected entities may include users that are part of the government or defense department.
Some incumbent users, however, may be willing to share spectrum if operations of in the incumbent user are not negatively affected or if financial compensation is made.
To date, the coordination of spectrum sharing arrangements for protected spectrum (e.g., licensed frequencies) has been a very tedious process that involves detailed human involvement.